Furnace discharging apparatus



Sept. 11, 1951 Filed Aug. 24, 1949 C. O. HAASE FURNACE DISCHARGING APPARATUS 4 Sheets-Sheet l I lNl ENTOR C O. HAAS E A T TORNE Y Sept. 11, 1951 c. o. HAASE FURNACE DISCHARGING APPARATUS 4 Sheets-Sheet 2 Filed Aug. 24, 1949 INVENTOR Ci 0. HAASE FIG. 2

ATTORNEY Sept. 11, 1951 Filed Aug. 24, 1949 'c. o. HAASE FURNACE DISCHARGING APPARATUS 4 Sheets-Sheet 4 FIG. 6

INVENTOR 3 6. 0, HAASE ATTORNEY Patented Sept. 11, 1951 FURNACE DISCHARGIN G APPARATUS Carl 0. Haase, Baltimore, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application August 24, 1949, Serial No. 112,052

10 Claims.

This invention relates to furnace discharging apparatus and more particularly to apparatus for discharging reels from annealing furnaces.

In annealing articles, such as copper wire wound on reels, the reels are sometimes conveyed through a steam filled chamber, and then are discharged one at a time from the chamber. When the reels are discharged precautions must be taken to prevent air from entering the chamber to prevent oxidation of the wire and to maintain pressure of the steam. Heretofore, there has been no satisfactory discharge device for discharging reels automatically from an annealing furnace without entrance of air into annealing chambers and without possibility of jamming the discharge devices.

An object of the invention is to provide new and improved furnace discharging apparatus.

A further object of the invention is to provide new and improved apparatus for discharging articles from annealing furnaces.

Another object of the invention is to provide new and improved apparatus for discharging articles from annealing furnaces with minimum entrance of air into the furnaces.

A furnace discharging apparatus illustrating certain features of the invention may include a chamber having an opening therein, a chute connected to the opening through whicharticles may travel, a plurality of seals extending transversely across the chute at spaced points therealong, and means foropening and closing the seals sequentially to permit an article to travel through the chute.

A complete understanding of the invention may be obtained from the following detailed description of apparatus forming specific embodiments thereof, when read in conjunction with the appended drawings, in which:

Fig. l is a fragmentary, side elevation of an annealing furnace including a furnace discharging apparatus forming one embodiment of the invention with portions thereof broken away;

Fig. 2 is an enlarged, fragmentary, vertical section taken along line 22 of Fig. 1;

Fig. 3 is an enlarged, fragmentary vertical section of a portion of the apparatus shown in Fig. 1;

Fig. 4 is an enlarged, fragmentary view of a portion of the annealing furnace;

Fig. 5 is a fragmentary, vertical section of an annealing furnace including a furnace discharging apparatus forming another embodiment of the invention, and

Fig. 6 is an enlarged, fragmentary diagrammatic view of a control circuit of the apparatus shown in Fig. 5.

Referring now in detail to the drawings, there is shown in Figs. 1 to 4, inclusive, an annealing furnace for annealing reels l0l0 (Fig. 1) continuously. The annealing furnace includes a furnace chamber l2 having an entrance opening I4 therein to which the reels l0l0 are advanced by a chain conveyer l5. Steam under pressure slightly greater than atmospheric pressure is introduced into the chamber l2 to prevent entrance of air therein. The chain conveyer advances the reels through an entrance chute I6 to a conveyer chain I6 mounted on sprockets 20 and 22. The sprocket 22 is driven by an electric motor 24 through a gear reducer 26, and is turned in a clockwise direction, as viewed in Fig. l, to advance the reels from the entrance opening I4 in the chamber l2 around the sprocket 22 to a discharge mechanism 28.

As each of the reels l0lll approaches the discharge mechanism 28, a fixed rod. 30 rolls the reel out of the chain conveyer 18 onto a receiving platform 32, through an opening 34 in the chamber 12 and into a chute 36 against a gate 38 (Fig. 3) mounted slidably in guideways 40-46 (Fig. 2) The gate 38 may be raised into a steam tight housing 42 positioned above an opening 44 in the housing chute 36 by pistons 46-46 (Fig. 2) mounted in cylinders 48-48. Racks 50-50 meshing with pinions 5252 mounted on a shaft 54 stabilize vertical movement of the gate.

The gate 38 serves to stop the reel H! in a position in which the reel depresses a shoe 56 against the action of a compression spring 5?. Depressing the shoe 56 moves a lever 58 in a clockwise direction, as viewed in Fig. 4. This causes the lever 58 to actuate a limit switch 69 and to actuate a four-way valve 62. Actuation of the switch 60 closes a circuit to an electric time delay relay, which will stop the motor 24 if the reel l0 does not roll off the shoe 56 before the expiration of a reasonable length of time. When the lever 58 is pivoted in a clockwise direction, as viewed in Fig. 4, it actuates the valve 62 (Fig. 4) to connect a high pressure hydraulic line 64 leading from a pump 66 (Fig. l) to a pipe 68 leading to a normally closed valve 70. Pipes l2, l3 and 14 connect a port 76 of the valve 10 to the lower ends of the cylinders 48-48 (Fig. 2). A port (Fig. 4) of the valve H3 is connected by a pipe 82 to an exhaust line 84 leading to the suction side of the pump 66.

The valve iii includes a spring-pressed plunger 8| normally in a position connecting the pipe 68 to the pipe I2 and preventing flow from the pipe "E2 to the pipe 82. When a lever 90 is in the position shown in Fig. 4, it actuates the plunger 8% of the valve I to prevent flow from the pipe 68 to the pipe 72 and to permit flow from the pipe E2 to the pipe 82. The lever 90 is held in this position when a gate 94 is in its closed position in which position a pin Q engaged by a lug 98 on the gate 9 holds the plunger BI out of its normal position.

Assuming that the gate at is closed so that the high pressure pipe 68 is connected to the pipe ?2 and a reel at the door 3% has actuated the valve $2 to connect the pipe 58 to the high pressure line t l, hydraulic fluid under pressure is supplied to the lower ends of the cylinders l8- i8 as viewed in Fig. 2, and the fluid raises the gate 38 into the housing 42. This permits the reel It to roll down the chute 36 until it engages a cushion IBI] on the gate 94. After the reel rolls off the shoe 5%, the spring 5? pivots the shoe in a counterclockwise direction, as viewed in Fig. 3. This swings the lever 58 in a counterclockwise direction, as viewed in Fig. 4', to actuate the valve E2 to connect the high pressure line 5 3 to a pipe I98 connected by pipes I08 and I IS to the upper ends of the cylinders l848 and connect the pipe E8 to a pipe [I2 connected to the exhaust line 84'. Then hydraulic fluid under pressure is supplied to the upper ends of the cylinders i8t8 and is exhausted from the lower ends of the cylinders, whereby the gate 38 is moved to a position sealing off the portion of the chute 36 behind the reel Id, and an angle IIG. secured to the upper portion of the gate 38 engages a resilient sealing strip H5. The gate S 1 carries an angle IIG, which engages a sealing strip II? when the gate 96 is closed.

When the reel it rolls to the gate 94, it depresses a shoe I29 against the action of a compression spring I22 and turns a lever I25, in a clockwise direction, as viewed in Fig. l. This actuates a valve I26 to connect the high pressure line 34 to a pipe I39 connected to a port I32 of a valve I34. If unrestrained, a plunger I35 of the valve I34 is spring pressed to a position in which it closes the port I32 from a port I37 and permits flow from the port I3? to a pipe E39. When the gate 38 is in its closed position, a pin I 33 is held by a lug 1452 on the gate 38 in a position holding a lever M 4 in a position in which the plunger I36 permits flow from the port I32 to the port I37 and prevents flow from the port I 3? to the pipe I39 connected to the exhaust line 85.

Assuming that the gate 38 is closed and that one of the reels I6 is at the gate fail depressing the shoe IZfi to actuate the valve I26, hydraulic fluid under pressure flows from the pipe I33 to the valve Hid, through pipes I52 and IM -I56 into the lower ends of cylinders I5%I58. The hydraulic fiuid under pressure forces the gate 94 to an open position. The hydraulic fluid initially in the cylinders is permitted to escape through the tops of the cylinders 'I58I58 to pipes I63, Hi2 and I65 to the valve I25 and through the valve I26 to the exhaust line 8 1, the valve I26 having been actuated positively by the reel Iil to connect the pipe I60 to the exhaust line 84. The gate 96 then is raised to its open position in a housing Il'il. The reel I9 is held back by the gate 94 until the reel clears it, and then rolls under the gate to a point outside the chute 36.

As the reel Ii] rolls off the shoe I2i and past the gate E l, the shoe I29 is urged upwardly, as viewed in Fig. 3, by the spring I22. This moveto a condition in which the high pressure line ment of the shoe I26 swings the lever I24 in a counterclockwise direction, as viewed in Fig. 4. This actuates the valve I25 to a condition connecting the pipe I38 to the pipe 84 so that the hydraulic fluid may be exhausted from the cylinders IEB-IES, and connecting the pipe I-i2 to the high pressure line 64. The hydraulic fluid then flows into the upper ends of the cylinders I58I58 and is exhausted therefrom. The fluid under pressure flows into the upper ends of the cylinders Hid-458 and moves the gate downwardly, as viewed in Fig. 3, to its closed position, in which position the lug d8 holds the lever $8 in a position holding the plunger SI of the valve 18 in a position connecting the pipe 83 to the pipe I2 so that the gate 33 may be raised by the next reel.

A manually operable control valve IBQ is operable to actuate a hydraulic drive I86 to raise and lower a gate I38. The gate I88 is in its raised or open position during the normal operation of the annealing furnace, and usually is moved to its closed position only during a shutdown of the annealing furnace.

Operation The reels Iii-it are introduced into the entrance chute I5 (Fig. 1) and are fed one at a time onto the chain conveyer I8, which carries them slowly through the chamber I2 in a clockwise direction, as viewed in Fig. 1. Steam under pressure is introduced into the chamber I2 to maintain a non-oxidizing atmosphere for the Wire on the reels. The filled reels are heated to annealing temperature by conventional heating devices (not shown). The reels are discharged periodically one at a time into the discharge mechanism 28 by the rod 39 which pushes the reels from the conveyer IS onto the inclined platform 32.

Each reel rolls from the platform 32 to a position against the gate 38 and depresses the shoe 56. This moves the lever 58 in a clockwise direction, as viewed in Fig. i, to actuate the valve E2 4 is connected to the pipe 68 and the exhaust pipe H2 is connected to the pipe I96. Then, if the gate 94 is in its closed position so that the lever 98 holds the plunger iii in the position connecting the pipe 68 to the pipe '52, the high pressure fluid flows into the lower portions of the cylinders Ll8-i8 to raise the gate 38, and the hydraulic fluid in the upper portions of the cylinders Z S- l8 flows through the pipes lid and IE3, the valve 62 and the pipe I I2 to the exhaust line 84.

As the gate 38 is raised from its closed position, the spring-pressed plunger I36 is urged to the right to block the pipe I52 from the pipe I38 to prevent raising the gate 9:: while the gate 33 is not in its closed position. The gate 38 is moved to its open position in a few seconds, and the reel rolls under the gate 38 to a position against the gate 94. As the reel rolls off the shoe 5%, the compression spring 5'! raises the shoe 56 and actuates the valve 52 through the lever 58 to reverse the direction of movement of the gate 38, and the gate 38 is moved from its open position to its closed position.

As the gate 38 approaches its closed position, the lug M2 (Fig. 2) moves the lever 4 2d through the pin I 40 to move the spring-pressed plunger toward the left, as viewed in Fig. 4, to connect the pipe I30 to the pipe I52. As'the reel engages the shoe I20 it depressesthe shoe to actuate the valve I26 to supply hydraulic fluid to the lower end of the cylinders I58I58 and raise the gate 94 from its closed position to its open position. After the gate 94 is moved from its closed position, the spring-pressed plunger 8| is free to move toward the right, as viewed in Fig. 4, thereby blocking flow of the fluid between the pipes 68 and 12 and connecting the pipes 12 and 82. As the gate 34 is lifted from its closed position to its open position, the reel rolls therepast and moves out of the chute 36 and off the shoe I26. This permits the shoe I26 to be raised by the spring I22, which action occurs to actuate the valve I26 to reverse the direction of the gate 94 and it is closed. As the gate 94 reaches its closed position, the lever 96 is actuated by the lug 98 to move the spring-pressed plunger BI to the left, as viewed in Fig. 4, thereby reconnecting the pipes 68 and 12 so that the gate 38 may be raised when the next reel depresses the shoe 56 (Fig. 2).

The above-described mechanism serves to seal the chamber l2 at all times since one of the doors 38 and 94 must be closed to permit the other door to be opened. Hence, steam is prevented from escaping from the chamber I2 through the chute 36 except the small volume that fills the space between the doors 38 and 94 less the volume occupied by one of the reels I6I6.

Embodiment shown in Figs. 5 and 6 An apparatus forming an alternative embodiment of the invention includes a steam-filled chamber 2E2 having a discharge opening 2M and a chain conveyor 2I8 for moving filled reels 2I6-2I6 through the chamber. The reels are moved one at a time from the chain conveyor by a rod 236 onto an inclined platform 232, and roll into a chute 236 of a discharge mechanism 228. Assuming that gates 238 and 294 are closed and that there is no reel in the space therebetween, when one of the reels 2 I 62 I 6 depresses a shoe 256 preceding the gate 238, the shoe closes a limit switch 266 to start a timer 26I associated with a motor controller 262 controlling a main drive motor 224 of the annealing furnace. The shoe also opens contacts 264 and 265 (Fig. 6) of a limit switch 263, and closes contacts 266 and 261.

A conductor 216 of a three-phase power line 212 is connected by a conductor 214 to a reversible motor 248. A conductor 216 of the power line is connected to one side of the contacts 266 by conductors 216 and 286 and to one side of the contacts 264 by conductors 218 and 282. A third conductor 284 of the power line is connected to one side of the contacts 261 by conductors 286 and 286 and to one side of the contacts 265 by conductors 286 and 296. Conductors 366 and 362 connect the contacts 266 to contacts 364 of a limit switch 366 controlled by the lug 298 on the gate 294, and conductors 368 and 3| 6 connect the contacts 261 to contacts 3 I2 of the switch 366. Conductors 3M and 3I6 connect the contacts 364 and 3I2, respectively, to the motor 248.

Conductors 3I8 and 3I9 connect the contacts 264 and 265, to contacts 322 and 324, respectively, of a limit switch 326 controlled by a lug 242 on the gate 238. Conductors 336 and 332 connect the contacts 322 and 324 to the conductors 3I6 and 362, respectively. The motor 248 serves to move the gate 238 (Fig. 5) vertically through a rack 334 and a pinion 336.

The gate 294 is opened and closed by a threephase reversible motor 346 through a pinion342 and a rack 344. The conductors 216, 216 and 284 of the power line 212 are connected to the motor 340, a contact 346 of a limit switch 348 and a contact 356, respectively, by a conductor 352, conductors 354 and 356 and conductors 358 and 366. The switch 348 is controlled by the position of a shoe 326, and also includes contacts 362 and 364 connected to the conductors 354 and 358, respectively, by conductors 366 and 368, and contacts 316 and 312, respectively, of the switch 366 by conductors 314 and 316, respectively.

The contacts 346 are connected to the motor 346 by conductors 318 and 380, contacts 332 of the switch 326 and a conductor 384, and a conductor 386 connects the contacts 316 to the conductor 366. The contacts 356 are connected to the motor 346 through a circuit including conductors 388 and 396, contacts 392 and a conductor 396, and a conductor 398 connects the contacts 312 to the conductor 396.

Operation of embodiment shown in Figs. 5 and 6 The reel 2I6 is ejected by the rod 236 from the chain conveyor 2I6 to the inclined platform 232 and comes to a rest against the door 238 depressing the inclined shoe 256. This closes contacts 266 and 261 to close the circuit to the motor 248 through the contacts 364 and 3I2 of the switch 366, and the motor 248 is driven in a direction in which the gate 238 is opened. The reel 2I6 then rolls down the chute 236 and comes to rest against the gate 294. As the reel 2| 0 rolls to this position the shoe 250 is raised to open the contacts 266 and 261 and close the contacts 264 and 265 to reverse the motor 248 through the contacts 322 and 324 of the switch 326 and the contacts 364 and 3I2. The gate 238 then is closed, and the lug 242 actuates the switch 326 to open the contacts 322 and 324 to stop the motor 248.

The actuation of the switch 326 closes the contacts 382 and 392 to permit energization of the motor 346. The reel 2I6 has depressed the shoe 226 by this time, which actuates the switch 348 to open the contacts 362 and. 364 and close the contacts 346 and 356. Closing of the contacts 346, 356, 382 and 392 causes energization of the motor 346 in a direction in which it raises the gate 294. After the gate 294 is moved from its closed position, the switch 366 returns to normal condition in which the contacts 364 and 3I2 are open to prevent opening the gate 238 and contacts 316 and 312 are closed to permit closing the gate 294 when the reel rolls off the shoe 326 and out of the chute. These occur as the gate reaches its open position, and the reel rolls off the shoe 326 to reverse the motor 346. The motor 346 then closes the gate, and is deenergized when the lug 296 actuates the switch 366 to close contacts 364 and 3I2 and open contacts 316 and 312 to deenergize the motor 346. The operation described hereinabove then is repeated on another of the reels 2 iii to be discharged.

The above-described discharge mechanisms prevent opening annealing furnaces to the atmosphere whenever a reel is discharged therefrom, and, in fact, always keep one of the gates closed while the other gate is opened so that entrance of air into the annealing chamber is prevented. These apparatus are completely automatic so that operators are free to perform other duties in connection with furnaces.

What is claimed is:

1. An annealing furnace, which comprises an annealing chamber having a discharge opening, a generally tubular, elongated chute extending from the discharge opening and sloping downthe means for actuating the gate-driving means to 7 wardly therefrom, a gate, means for opening and closing the gate, a second gate spaced along the chute from the first-mentioned gate a distance sufficient to permit an article to be therebetween, means for opening and closing the second-mentioned gate, means for driving the first-mentioned gate, article-actuable means for actuating the gate-driving means to open the first-mentioned gate when an article is at the approach side of the first-mentioned gate and for actuating the gate-driving means to close the first-mentioned gate when there is no article at the approach side of the gate, means associated with the second-mentioned gate for preventing operation of the gate-driving means when the second-mentioned gate is not in a closed position and permitting operation of the gate-driving means when the second-mentioned gate is in a closed position, means for driving second-mentioned gate, articre-actuable open the second mentio'ned gate when an article .is in the portion of the chute between the gates and to close the second-mentioned gate when there is no article in that portion of the chute, and means associated with the first-mentioned :gate for preventing operation of the second-mentioned gate-driving means when the first-mentioned gate is not in a closed position and per- 1mitting operation of the second-mentioned gatedriving means when the first nientionetl gate is in a closed position.

positioned at a predetermined point along the chute and movablebetween a closed position and .an open position for sealing the chute when in :the closed position thereof and permitting travel of an article when in the open position thereof,

.a second gate positioned at a .point along the chute spaced from the first-mentioned gate sufficient to permit an articleto' be between the gates :and movable between a closed position in which it seals the chute and an open position in which :it permits travel of an article, means for moving the first-mentioned gate toiopen andlclose that gate, means positioned on the approach side of the first-mentioned gate in the path ofan article for actuating the gate-movingmeansto open that gate when engaged by an articlean'd close the gate when not engaged by an articles, means for moving the second-mentioned gate to open and close that gate, means positionedbetween the gates in the path of an article for. actuating the second-mentioned gate-moving means to open the second-mentioned gate when engaged by an article and close the gate when not engaged by an article, means operable by the first-mentioned gate for preventing opening of the second-menticned gate when the first-mentioned gate. is not closed, and means operable by the second-mentioned gate for preventing opening of the firstmentioned gate when the second-mentioned gate is not closed. 7

3. An annealing furnace, which comprises an article-processing chamber having an opening therein, a generally tubularvchute-,connected: to the opening for guiding articles advanced by gravity from the entrance end thereof to the exit end thereof and for sealing the opening, a gate positioned at a predeterminedpointalong the chute and movable between a closed position and an open position for sealing the chute when in the closed position thereof and permitting travel of an article when in the open position thereof, a second gate positioned at a point along the chute spaced from the first-mentioned gate sufficient to permit an article to be between the gates and movable between a closed position in which it seals the chute and an open position in which it permits travel of an article, means for moving the first-mentioned gate to open and close that gate, means positioned on the approach side of the first-mentioned gate in the path of an article for actuating the gate-moving means to open that gate when engaged by an article and close the gate when not engaged by an article, means for moving the second-mentioned gate to open and close that gate, and means positioned between the gates in the path of an article for actuating the second mentioned gate moving means to open the second-mentioned gate when engaged by an article and close the gate when not engaged by an article.

4. An annealing furnace, which comprises an annealing chamber having a discharge opening, a generally tubular, elongated chute extending from the discharge opening and sloping downwardly therefrom, a gate, hydraulically operable means for opening and closing the gate, a second gate spaced along the chute from the first-mentioned gate a distance sufficient to permit an article to be therebetween, hydraulically operable means for opening and closing the second-mentioned gate, a source of liquid under pressure, means including a valve for connecting the source of liquid to the first-mentioned gate-openingand-closing means to open the first-mentioned gate when in one condition and connecting the source of liquid to that gate-opening-and-closing means to close the first-mentioned gate when in a second condition, article-actuable means for actuating the valve to place it in the first-mentioned condition when an article is at the approach side of the first-mentioned gate and to place the valve in the second-mentioned conditionthereof when there is no article at the approach side of the gate, a second valve in series with the first-mentioned valve, means associated with the second-mentioned gate for closing the second-mentioned valve when that gate is not in a closed positionand opening that valve when that gate is in a closed position, means including a third valve for connecting the source of liquid to the second-mentioned gate-opening-and-closing means to open the second-mentioned gate when in one condition and to close that gate when in a second condition, article-actuable means positioned between the gates in the path of an article for actuating the third-mentioned valve to place it in the first-mentioned condition when an article is in the portion of the chute between the gates and to place that valve in the second-mentioned condition thereof when there is no article in that portion of the chute, a fourth valve in series with the third-mentioned valve, and means associated with the first-mentioned gate for closing the fourth-mentioned valve when that gate is not a closed position and for opening that valve when that gate is in a closed position.

5. An annealing furnace, which comprises an annealing chamber having a discharge opening, a, generally tubular, elongated chute extending from thedischargeopening and sloping. downwardly therefrom, a gate, a reversible electric motor for opening and closing the gate, a second gate spaced along the chute from the first-mentioned gate a distance sufficient to permit an article to be therebetween, a second reversible electric motor for opening and closing the secondmentioned gate, a source of electrical difference of potential, a reversing limit switch for connecting the source of electrical difference of potential to the first-mentioned motor to open the first-mentioned gate when actuated by an article at the approach side of the first-mentioned gate to close the first-mentioned gate when there is no article at the approach side of the firstmentioned gate, a second switch in series with the first-mentioned switch, means associated with the second-mentioned gate for opening the second-mentioned switch when that gate is not in a closed position and closing that switch when that gate is in a closed position, a second reversing limit switch for connecting the source of electrical difference of potential to the second-mentioned reversible motor to open the second-mentioned gate when actuated by an article is in the portion of the chute between the gates to close that gate when there is no article in that portion of the chute, a fourth switch in series with the third-mentioned switch, and means associated with the first-mentioned gate for opening the fourth-mentioned switch when that gate is not in a closed position and closing that switch when that gate is in a closed position.

6. An apparatus for discharging an article from an annealing furnace, which comprises a discharge passageway extending from the annealing furnace, a plurality of sealing gates mounted at spaced points along the passageway. means responsive to an article moving along the passageway for successively opening the gates so that the article may move therepast, and control means responsive to the position of one of the gates for keeping another one of the gates completely closed while the first-mentioned gate is even partially open.

'7. An apparatus for discharging an article from an annealing furnace, which comprises a discharge passageway extending from the annealing furnace, a plurality of sealing gates mounted at spaced points along the passageway, means responsive to an article moving along the passageway for opening the first gate encountered by the article so that the article may move therepast, means responsive to the position of a succeeding gate for preventing the first gate from opening unless said succeeding gate is closed, means responsive to the article for opening -said succeeding gate, and means for preventing said succeeding gate from opening unless the first gate is closed.

8. An apparatus for discharging an article from an annealing furnace, which comprises a discharge passageway extending from the annealing furnace, a plurality of movable gates mounted at spaced points along the passageway, each of said gates being designed to prevent the movement of an article along the passageway and to form a gas-tight seal across the passageway when closed, means responsive to the weight of an article positioned adjacent to the first gate encountered for opening said first gate so that the article may be advanced to a succeeding gate, means responsive to the position of said succeeding gate for preventin the first gate from opening unless said succeeding gate is closed, said weight responsive means being operative to close the first gate after the article has been advanced past said weight responsive means, means responsive to the weight of the article when the article is positioned adjacent to said succeeding gate for openin said succeeding gate,

and means for preventing said succeeding gate from opening unless the first gate is closed.

9. An apparatus for discharging an article from an annealing furnace, which comprises a downwardly inclined discharge passageway extending from the annealing furnace, a plurality of movable gates mounted at spaced points along the passageway, each of said gates being designed to halt the movement of an article advanced by gravity down the passageway and to form a gastight seal across the passageway when closed, means responsive to an article halted against the first gate encountered by the article for opening said first gate so that the article may advance to a succeeding gate, means responsive to the position of said succeeding gate for preventing the first gate from opening unless said succeeding gate is closed, means responsive to said article when it is halted against said succeeding gate for opening said succeeding gate, and means responsive to the position of said first gate for preventing said succeeding gate from opening unless the first gate is closed.

10. An apparatus for discharging an article from an annealing furnace, which comprises a downwardly inclined discharge passageway ex-- tending from the annealing furnace, a pair of vertically slidable gates mounted at spaced points along the passageway, each of said gates being designed to halt the movement of an article advanced by gravity down the passageway and to form a gas-tight seal across the passageway when closed, a spring-pressed shoe designed to be depressed by the article when the article is halted against the first gate encountered, control means actuated by the shoe for raising the first gate when the shoe is depressed to permit the article to advance to the second gate and for closing the first gate when the shoe is not depressed, means actuated by the second gate for preventing the first gate from opening unless the second gate is closed, a second springpressed shoe designed to be depressed by the article when it is halted against the second gate, a second control means actuated by the second shoe for raising the second gate when the second shoe is depressed and for closing the second gate When the second shoe is not depressed, and means actuated by the first gate for preventing the second gate from opening unless the first gate is closed.

' CARL O. HAASE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 890,251 Thompson June 9, 1908 1,711,100 Payzant Apr. 30, 1929 FOREIGN PATENTS Number Country Date 474,940 Germany Apr. 15, 1929 

